Like other's have mentioned, if you have a buffer it's ideal, because once you post--that's basically the order your story is now (hopefully one day they'll fix that) and even then, trying to fiddle with things in your scheduled updates is a pain the ass. I decided to add a 10-part chapter to my backlog, and it took nearly an hour to shuffle everything around, because I had to manually change the update schedule on every single episode after that chapter. (and now I'm hella paranoid I did it wrong.) So it's fine to write by the seat of your pants, but maybe finish your story before you start posting it because once you commit, you are committed.
For this reason I have hella short updates, about 3,000-5,000 characters each (which is about 500-900 words), because later when I'm reading through it again for spell checking and grammar checking reasons, and I feel like I want to add stuff (and I will do that quite a bit) I have room to add the stuff I want to say. Don't go too close to the limit or you are basically trapped in that wordcount. It's weird because in webcomics we are pressured to have as long of episodes as possible, and people will comment demanding longer updates, but in Tapas novels--nah. There's no pressure to do that.
Another thing is that you can add art! There's a few threads on here on how to do it--and I highly recommend having something visual in the first few updates, if you can draw. That and you can add music from soundcloud with each update, which I do, and I think only a few people use it, but it is a fun feature I didn't know was here for quite a while and I enjoy reading novels that have music attached.
And finally, if you do make changes to your past updates--don't notify your followers that you have or it will every, single, time, and it bothers people. They'll be notified when you update--that's what they're looking for. They don't really care if you changed spellings or moved around some sentences.